1. Field of the Invention
The present invention relates to dispensers operating according to the pump principle. In addition, the present invention refers to a dispensing pump itself as well as to a dispenser unit-assembly.
2. Brief Description of the Prior Art
Dispensers operating according to the pump principle are generally known from the prior art. Such dispensers are provided with a pumping head and a storage container connected thereto. Up to now, the storage container and the pumping head have, however, been individually adapted to one another in the case of such dispensers so that one pumping head always matches only one specific storage container. The design and manufacturing expenditure for such dispensers is correspondingly high.
In view of the manifold possibilities of use of dispensers, there is, however, an interest in reducing this expenditure.
Hence, it is the object of the present invention to create a dispensing pump having manifold uses. Furthermore, it is the object of the present invention to provide a suitable dispenser as well as a dispenser unit-assembly.
This object is achieved by a dispensing pump implemented as modular functional unit and comprising a piston body having a piston section and a cylinder body having a cylinder section, said piston section being slidably accommodated in said cylinder section and both said elements defining a pump chamber together, further comprising an inlet channel and an outlet channel connected via the pump chamber, a respective check valve being arranged in each of said channels, and still further comprising a resetting device arranged between the piston body and the cylinder body as well as limiting devices which are provided on said piston body and said cylinder body and which are adapted to be brought into engagement with one another.
In this way, a particularly compact dispensing pump is obtained, which is adapted to be used with a large number of dispensers whose head piece and storage container can have an arbitrary structural design.
Preferably, the limiting devices come into contact with one another when the maximum pump-chamber volume has been reached so as to limit the relative movement between the piston body and the cylinder body beyond the maximum pump-chamber volume. Due to the fact that the limiting devices are formed on the piston and on the cylinder body, additional holding elements, which are often used in the prior art, can be avoided. This will reduce the variety of parts used in the dispensing pump so that it will suffice to have a smaller number of parts in stock and so that a more efficient assembly will be possible. The limiting devices also serve the purpose of preventing the pump from falling apart.
Preferably, the piston body and the cylinder body are each bell-shaped, one of them being inside the other, said piston body and said cylinder body defining the modular dispensing pump. The limiting projections restrict the mamximum pump-chamber volume. Due to the bell-shaped configuration, the dispensing pump has a capsular structural design on the outer side thereof, which contributes to a reduction of the structural volume. A dispensing pump having this kind of structural design can be used with a great variety of different dispensers.
The axial overall length of the dispensing pump is shorter in the compressed condition than in the extended condition where the pump chamber has its maximum volume. Hence, the dispensing pump can be used with dispensers in which, when a dispensing key is being pressed down, also the outlet opening moves as well as with dispensers in which the outlet opening is not movable.
Preferably, the two check valves of the dispensing pump are implemented as annular gap valves with annular valve bodies. This permits the medium to flow uniformly into the pump chamber and a discharge channel so that, especially in the case of pasty media, asymmetric dead zones in the flow path will be avoided.
According to a further advantageous embodiment of the present invention, the limiting devices on the piston body and the cylinder body are provided as projections on opposed walls, said projections being in sliding engagement with the respective opposed wall so as to improve the guiding effect and so as to prevent the piston-cylinder arrangement from tilting. This permits a long service life of the re-usable dispensing pump.
The above-mentioned object is also achieved by a dispenser for dispensing flowable, e.g. fluid and/or pasty media, said dispenser comprising a storage container provided with a storage chamber for accommodating the medium to be dispensed, a head piece provided with a dispensing opening, and a pumping means provided with a pump chamber delimited by check valves on the inlet as well as on the outlet side thereof, the pumping means being implemented as a modular dispensing pump and being adapted to be connected to the head piece and/or the storage container via locking connections or screw connections.
Due to the fact that the storage chamber provided in the storage container is delimited by an outer wall of the dispensing pump in the axial direction, a corresponding wall on the storage container can be dispensed with. The storage container can thus be manufactured more easily. Due to the modular structural design of the storage container, the dispensing pump and the head piece, the dispensing pump can be assembled separately from the other parts so that, subsequently, it can be assembled with the storage container and the head piece in an efficient manner.
In the above-mentioned dispenser, the storage container is preferably implemented as a cylindrical body having at the top end thereof an upper opening, which extends across the whole cross-section of the storage chamber. For example, a follow-up piston delimiting the storage chamber or an insert container with a follow-up piston can be inserted into the storage container from the top end thereof in this way. The storage container can then also be filled from this side so that all the assembly steps can be carried out from the same side of the storage container.
According to a preferred embodiment of the dispenser, the head piece is fixed directly to the storage container in the assembled condition. Forces acting on the head piece from outside can thus be prevented from being transmitted directly on the dispensing pump. In addition, the fixing force that can be realized between the head piece and the storage container is stronger than the fixing force which could be realized if the head piece were fixed directly to the dispensing pump, since, if the dispenser is reused, i.e. if the storage container is exchanged or refilled and the head piece released, there will be no risk of damage being caused to the dispensing pump. Hence, a stronger fixing force between the head piece and the storage container can be chosen so that the head piece is saveguarded against being lost with a high degree of reliability.
Preferably, the separate dispensing pump is provided with at least one fastening projection abutting on the storage container and on the head piece in the assembled condition. This has the effect that the dispensing pump is secured in position in the dispenser without being fixedly connected to the head piece or the storage container. This will substantially simplify the assembly, since the dispensing pump only has to be inserted between the storage container and the head piece, whereas the fixing in position of said dispensing pump will be effected by fixing the head piece to the storage container. Alternatively, the dispensing-pump part arranged on the side of the storage chamber can also be secured to the storage container itself.
According to one advantageous further development of the dispenser, a bellows enclosing the medium to be dispensed is arranged in the storage container. The medium to be dispensed is therefore no longer in direct contact with the inner wall of the storage container, but the storage chamber is provided within the bellows. This permits simple and neat filling and especially refilling of the storage container.
Furthermore, the above-mentioned object is achieved by a dispenser unit-assembly system comprising head pieces, storage containers and at least one pumping means or dispensing pump, a respective head piece, storage container and dispensing pump defining together a dispenser in the case of which various head pieces can be combined with the same pumping means.
Advantageous further developments of the present invention are disclosed in the additional subclaims and the description following hereinbelow.